Passing to error handler the message sent from SMTP server when an error occour

This is useful to allow take some action regarding the message and the code that was returned.
Merge pull request #39 from andremetzen/patch-1

Passing to error handler the message sent from SMTP server when an error occurred
Added raw message to error object

I think it's important to know exactly what happened
Merge pull request #40 from andremetzen/patch-1

Added raw message from server to error object
minor adjustments for better portability with browserify
Merge pull request #41 from whiteout-io/browserify

minor adjustments for better portability with browserify
Bumped version to 0.3.7
short fix for #42
Merge pull request #42 from dannycoates/i42

Client parser hangs on certain input
Bumped version